Hi, I have Mctd-schleraderma, and more but I wonder has your sister done blood tests for the underlined MCTD immune disorders and I am surprised she hasn't at least been on steroids and other things in order to help her and pain meds as well for the time being. Is she seeing a Specialist? because she really needs to especially one that deals with this because it can be painful and itchy-mine is on my face so I know. please look up a mctd-RA-Lupus type specialist in your area and get a second opinion be sure to tel them what you are experienceing they really do not need the info from the doctor you have now and most insurances pay for second opinions. I hope this helps you let us know ok, g
Have you contacted a pain specialist in your area?